Identification of Vibrio metschnikovii from Homarus americanus and its changes in membrane fatty acid composition in response to low temperature

Abstract:

Abstract:［Objective］Bacterial strain F5-1 isolated from the Homarus americanus was characterized and its changes in membrane fatty acid composition in response to low temperature were also studied．［Methods］ The physiological and biochemical characteristics were carried out by using VITEK 2 compact automated microbiology system．The 16S rRNA gene was sequenced and subjected to phylogenetic analysis．Fatty acids were detected by gas chromatography-mass spectrometry (GC-MS)．［Results］Strain F5-1 was Gram-negative and susceptible to the vibriostatic agent O /129．Strain F5-1 was resistant to Penicillin．The isolated strain exhibited the highest levels of 99% probability to Vibrio metschnikovii based on the conventional physiological test． The sequence analysis of 16S rRNA gene of F5-1 isolation and comparison with that of other related vibrios showed that F5-1 was very close to V．metschnikovii (GenBank No．HQ658055)．The similarity was 99%．The major fatty acids were C12∶0，C14∶0，C16∶0 and C16∶1 (n-7)．Palmitoleic acid was the dominant unsaturated fatty acids．The major change in fatty acid composition occurred in response to low temperature，with an increase in palmitoleic acid from 34% to 40%．［Conclusion］Bacterial strain F5-1 isolated from Homarus americanus was identified as V．metschnikovii and was sensitive to multiple drugs．The fatty acid composition of F5-1 was different from V．metschnikovii isolated from a drinking water reservoir near Vladivostok City in the Russia Far East．Results of this study indicated that environmental conditions allowed modulation of the fatty acid composition of V．metschnikovii．